Cultivation system

ABSTRACT

A system for cultivating a crop includes a guide and a plurality of gutters. Each gutter is provided to contain a plurality of crop units and the guide is provided to guide the gutters in a first direction and to gradually increase the distance between adjacent gutters in said direction so that the number of crop units per square metre in the area substantially decreases. The area comprises first and second zones, and each gutter in the first zone contains crop units with a first intermediate distance and each gutter in the second zone contains crop units with a second intermediate distance. The first intermediate distance is considerably smaller than the second intermediate distance and the distance between gutters in the first zone at the position of a transition from the first zone to the second zone is considerably greater than the distance between gutters in the second zone.

CULTIVATION SYSTEM

This is a national stage application filed under 35 U.S.C. 371 ofinternational application PCT/BE2016/000030, filed Jun. 28, 2016, whichclaims priority to Belgian patent application BE 2015/5409, filed Jun.30, 2015, the entirety of which applications are incorporated byreference herein.

The present invention relates to a system for cultivating a crop. Theinvention relates particularly to a system for cultivating a crop bymeans of hydroponics.

Hydroponics is the growing of plants in water to which the necessarynutrients have been added. It is a cultivation method which is appliedincreasingly often, not only for house plants but also for cultivationof vegetables, such as tomato, chicory, lettuce and other crops, in aprotected space (glasshouse or building) or outside. An importantadvantage of hydroponics relative to soil cultivation is that water andnutrients can be dosed in simple and precise manner. Soil-bound diseasesusually do not occur, and there is thereby much less need for treatmentwith agents against disease.

Cultivating a crop in hydroponics typically comprises multiple stages. Afirst stage is the sowing and germination stage. Different units ofmedium (substrate) are first placed, optionally packaged (soil block(root ball), potting compost, pot, net, . . . ), in a receptacle ortray. One or more seeds are then placed in or on the medium. The numbercalculated per m² varies from 200 to more than 1000, depending on thedimensions of the medium and the type of seed. The germination stagetakes place in a germination chamber (germination cell). Temperature andmoisture are mainly controlled here in order to bring about optimalgermination of de seed. After germination, the receptacles/trays aredisplaced from the germination space to the glasshouse, where the plantscan grow to a determined size. This is the raising stage. After theraising stage, the plants are usually carried from the plant grower tothe market gardener. At the market gardener with a hydroponics system ingutters the plants will be transplanted to a tray. One density of 100per m² is usually applied. This stage is referred to as the extendedraising stage. Water, optionally with fertilizers, is supplied onto thetray via overhead irrigation. The extended raising stage is followed bythe cultivation stage. In the cultivation stage the plants are typicallyplaced in gutters which are provided to slide apart as the crop grows,such that the crop has space to reach full growth while the surface areais utilized optimally.

WO 94/07354 describes a system of movable gutters for cultivating acrop. This system is typically used in the cultivation stage. WO94/07354 describes a system for cultivating a crop with a guide forguiding a plurality of gutters in a predetermined area, wherein eachgutter is provided to contain a plurality of crop units of a crop andwherein the guide is provided to guide the gutters in a first directionextending from a first edge to a second edge of the area, wherein theguide is further provided to gradually increase the distance betweenadjacent gutters in said direction, such that the number of crop unitsper m² in the area substantially decreases from the first edge to thesecond edge. A surface area in a glasshouse can in this way be utilizedoptimally when hydroponics is applied, wherein the advantages ofhydroponics relative to soil cultivation are described above.

It is an object of the present invention to further optimize the processof cultivating a crop.

The invention has for this purpose the feature that the area comprises afirst zone adjacent to the first edge and a second zone adjacent to asecond edge, and wherein each gutter in the first zone is provided tocontain crop units with a first intermediate distance and wherein eachgutter in the second zone is provided to contain crop units with asecond intermediate distance, wherein the first intermediate distance isconsiderably smaller than the second intermediate distance and whereinthe distance between adjacent gutters in the first zone at the positionof a transition from the first zone to the second zone is considerablygreater than the distance between adjacent gutters in the second zone atthe position of the transition.

Because the area with gutters now comprises two zones and the crop unitsin the first zone are positioned considerably closer together in thegutters, it is possible in this first zone to optimally fill theavailable surface area with plants which are considerably smaller thanin a prior art gutter system. The gutters in the first zone move apartas the small plant grows, until the transition location between thefirst zone and the second zone is reached. The plants or crop units arethen at least partially transplanted to the second zone, where theintermediate distance in the longitudinal direction of the gutterbetween the crop units is considerably greater than in the first zone.The plants are hereby given considerably more space in the longitudinaldirection of the gutter, and the distance between adjacent gutters cantherefore be considerably reduced. It is noted here that the plants ofthe mutually adjacent gutters are preferably positioned in a triangularpattern. The gutters can then be moved apart in the second zone as thecrop grows, such that the crop can be harvested when the gutters reachthe second edge and the crop has then also reached full growth.

Tests have shown that constructing the system for cultivating a crop inthis way enables considerable optimization of the extended raising stageas well as the cultivation stage. The plants are traditionally placed ontrays (in receptacles) in the extended raising stage, typically at themarket gardener. Crop units in such receptacles or trays areconsiderably more difficult to provide with water and nutrients thancrop units in gutters. Because the trays or receptacles are irrigatedfrom above, the distribution of water and nutrients is further nothomogeneous. This often causes crop units located at the edge of a zoneto dry out, which results in losses. Watering the crop by means ofirrigation is further considerably less efficient than watering in agutter. It has also been found that the roots of the crops growconsiderably less well on the sides of tray or receptacle zones than inthe gutter, this because they are often subjected to drying out and tolight in the receptacle or tray. The root of a tray plant is not thesame root as a root which is continuously wet owing to the nutrientsolution (water with fertilizers) flowing intermittently through thegutter. The intermittent watering is fully computer-controlled, and oncethe start time and end time have been set (a combination of time-basedstarts and light-based starts (until a threshold value of the light isreached)) the times at which the plants must receive nutrient water neednot be given any more thought. In the tray (receptacle) zone this iscompletely different and cannot be automated, and the area surroundingthe root constantly varies between wet and dry area.

Because the system according to the invention allows relatively smallplants to be placed in gutters in an optimal manner, plants coming fromthe raising stage can be placed directly in gutters. When these plantsare placed in the gutters, watering can take place in optimal manner,roots of the plants can develop properly because they are subjected muchless to drying air (and also light), and no losses will occur due touneven or irregular watering. Along the transition from the first to thesecond zone at least part of the plants are transplanted, wherein theintermediate distance of adjacent plants in a gutter is considerablygreater.

An unexpected and surprising advantage has surfaced in the transplantingor transferring of the plants from gutters in the first zone to guttersin the second zone. It has been ascertained in this transplanting ortransferring of the plants to gutters in the second zone that the plantsexperience no appreciable stress because the roots have alreadydeveloped in a gutter with an intermittent throughflow of a nutrientsolution. This is the same in the second zone, and the plant therebycontinues to grow optimally. This is in contrast to the transplanting ofplants from a tray or receptacle to a gutter. When plants from areceptacle or tray are planted in a gutter, the plant experiences stressbecause the manner of watering and fertilizing is different. A plant ina tray field is in practice watered a maximum of twice per day insummer, and is in winter even watered only a few times per week. Thisdiscontinuous watering results in a different type of root (an aerialroot) being formed. The tray plant which is transplanted into a gutterhas to adapt to this change from discontinuous (from several times perweek to a maximum of twice per day) to intermittent watering (from sixtimes per day in winter to more than double that in summer), whichcauses stress (production of new roots), whereby the rate of growth ofthe plant suffers a setback. Because transferring takes place from onegutter to another gutter in the system according to the invention, thearea surrounding the plant and root remains substantially the same andthe plant will experience no appreciable stress. In the case of trayplants a lag in growth of a few days can easily occur.

The stepwise increase in intermediate distance between adjacent plantsin a gutter is at least partially compensated in that the distancebetween adjacent gutters in the second zone is considerably smaller atthe position of the transition than the distance between adjacentgutters in the first zone at the position of the transition. The surfacearea remains optimally utilized hereby.

The ratio of the first intermediate distance and the second intermediatedistance and the ratio of the distance between adjacent gutters in thesecond zone and the first zone at the position of the transition ispreferably such that the number of crop units per m² remainssubstantially constant along the transition. Crop units per m² remainingsubstantially constant is defined here as the difference in the numberof crop units per m² being smaller than 25%, preferably smaller than20%, more preferably smaller than 15%. Because the number of crop unitsper m² remains substantially constant, the surface area can remainoptimally utilized along the transition from the first zone to thesecond zone. It is noted in this respect that the system with movablegutters has for its object to substantially continuously increase theavailable surface area per crop unit. The substantially continuousincrease can also take place in small steps here, and along thetransition from the first zone to the second zone such a step can beperformed such that the transition does indeed display an absolute jumpin number of plants per m². Such a jump is however still consideredsubstantially constant because this jump is considerably smaller thanthe difference in number of plants per m² at the position of the firstedge and the second edge.

The guide preferably comprises a drive for moving the gutters in thefirst direction, wherein the drive is provided to change the distancebetween adjacent gutters in said direction. Such a drive can be formedin different ways, for instance by a robot, or by a drive rod or pullrod or drive chain with catches which are placed at a mutual distancecorresponding to the distance between the gutters. One or more of suchdrives can be provided here, wherein a plurality of drives is forinstance each time provided to drive one segment of the area.

A device is preferably further provided for transplanting at least partof the crop units along said transition from the first zone to thesecond zone. This device can be fully automated or can requireintervention by a worker, wherein the device is for instance provided toposition a full gutter of the first zone adjacently of one or moregutters of the second zone, such that a worker can manually transfer theplants from the gutter of the first zone to the gutter or gutters of thesecond zone. A device can alternatively be provided for automaticallylifting at least part of the crop units from the first zone and placingthese lifted crop units in gutters of the second zone.

The device is preferably provided to transplant all crop units fromgutters in the first zone to gutters in the second zone. When all cropunits are transferred from gutters of the first zone to gutters in thesecond zone, the gutters of the first zone can be optimized forrelatively small plants while the gutters of the second zone areoptimized for relatively larger plants.

Each gutter preferably comprises a plurality of means for containing acrop unit, this plurality of means having predetermined intermediatedistances in the longitudinal direction of the gutter. The gutters arehere preferably substantially tubular or U-shaped in cross-section witha cover (lid), wherein the plurality of means are formed as openings inthe tube or cover, wherein each opening is formed to contain one or morecrop units such that the medium and roots of the crop unit are situatedsubstantially under the cover while leaves of the crop unit are situatedsubstantially above the cover. This gutter construction is found to havea number of advantages, the intermediate distance between adjacent cropunits is on the one hand predetermined and can thus be optimized. Thecover will on the other hand ensure that less light reaches the roots ofthe crop units, so that these roots can grow. The cover further ensuresthat water in the gutter does not evaporate directly from the gutter.

The gutters are preferably placed in draining manner and the systemcomprises at the position of an end of the gutters a water dosing systemand at the position of the other end of the gutters a water collectingsystem, such that the nutrient water flows through the gutters incontrolled manner through the use of the system. The water collectingsystem is more preferably operatively connected to the water dosingsystem (for instance by a collecting tank), such that substantially allnutrient water can be recuperated. A closed circuit in which the waterwith the nutrients flows is obtained in this way. This allows for waterand fertilizers to be handled highly efficiently and for water to leaveonly through evaporation, and fertilizers through uptake by the plant.

A plurality of water dosing systems and a plurality of water collectingsystems are preferably provided such that a different quantity of waterand/or water with different properties can be supplied to variousgutters. This plurality of nutrient water dosing systems and collectingsystems can then be placed in predetermined segments of the area so thatthe nutrient water (water with fertilizers) can be optimized dependingon the growth stage which the crop is in. It will be apparent here thatsmall plants have different needs than large plants.

The system preferably further comprises a raising zone with a furtherguide for guiding a plurality of raising gutters in a further areaadjacent to the first edge, wherein each raising gutter is provided tocontain a plurality of the crop units with a further intermediatedistance which is considerably smaller than the first intermediatedistance, wherein the guide is provided to gradually increase thedistance between adjacent raising gutters in said direction and whereinthe distance between adjacent raising gutters at the position of afurther transition from the raising zone to a first zone is considerablysmaller than the distance between adjacent gutters at the position ofthe further transition, such that the number of crop units per squaremetre remains substantially constant along the further transition. Justas in the transition from the first zone to the second zone, it is theintention that there is no sharp transition here from for instance 200to 100, but that the drop in the number of units/m² follows acontinuously declining trend. This raising zone is thus optimized bymaking use of gutters. The intermediate distance between plants in araising zone is considerably smaller here than the intermediate distancebetween plants in the first zone. This allows the surface area to beoptimally utilized. This also makes it possible to give the plants morespace in the raising stage by moving raising gutters apart as the plantgrows in the raising stage. This allows the whole system to be optimizedfurther, wherein the raising stage is for instance longer, wherein theplant can become bigger than in a raising stage carried out in thetraditional manner. The transition location between the extended raisingstage and the cultivation stage can in the system according to theinvention also be chosen so as to further optimize the growth of thecrop, the production process and the surface area utilization. This isnot possible in traditional systems, even if the cultivation stage iscarried out in movable gutters.

The invention further relates to a method for cultivating a crop,wherein the method comprises the following steps of:

planting units of a crop in a plurality of gutters at the position of afirst edge of a predetermined area;

guiding a plurality of gutters in a first direction which extends fromthe first edge to the second edge of the area, wherein the distancebetween the adjacent gutters gradually increases during the guiding suchthat the number of crop units per m² decreases from the first edge tothe second edge;

harvesting the crop units at the position of the second edge;characterized in that the method further comprises of:

transplanting at least part of the crop units along a transition fromthe first zone of the area adjacent to the first edge to a second zoneof the area adjacent to the second edge, such that each gutter in thefirst zone is provided to contain crop units with a first intermediatedistance and each gutter in the second zone is provided to contain cropunits with a second intermediate distance, wherein the firstintermediate distance is considerably smaller than the secondintermediate distance and wherein the distance between adjacent guttersin the first zone at the position of the transition is considerablygreater than the distance between adjacent gutters in the second zone atthe position of the transition. This method describes the use of thesystem described above. The effects and advantages described abovetherefore also apply for the method according to the invention.

The method preferably further comprises of advancing at least part ofthe plurality of gutters in said first direction by means of a drive.

The invention will now be further described on the basis of an exemplaryembodiment shown in the drawing.

IN THE DRAWING

FIG. 1 shows a schematic top view of a cultivation system according toan embodiment of the invention;

FIG. 2 shows a side view of a zone of a cultivation system of FIG. 1;

FIG. 3 shows a perspective view of a gutter for application in thecultivation system according to the invention;

FIG. 4 shows a cross-section of a gutter with crop unit;

FIG. 5 shows a schematic illustration of a greenhouse with a pluralityof systems according to the invention;

FIG. 6 shows different gutters from different zones of a preferredsystem according to the invention;

FIG. 7 shows a preferred drive system for application in the cultivationsystem according to the invention; and

FIG. 8 shows a graph which illustrates the effect of the cultivationsystem according to the invention.

The same or similar elements are designated in the drawing with the samereference numerals.

FIG. 1 shows a top view of a system for cultivating a crop according toan embodiment of the invention which is placed in a predetermined area1. This predetermined area 1 is in practice preferably formed by agreenhouse or glasshouse or an outdoor installation. A section of agreenhouse or glasshouse can here also form the predetermined area,wherein another section of the greenhouse or glasshouse is used forother purposes. It is also possible for a plurality of systems forcultivating a crop according to the invention to be placed in onegreenhouse or glasshouse, which is illustrated in FIG. 5. A first edge 2and a second edge 3 can be defined in predetermined area 1. First edge 2and second edge 3 are situated opposite each other and define a firstdirection extending from first edge 2 to second edge 3. This firstdirection is the direction in which the crop will move duringcultivation. The predetermined area 1 further comprises lateral sides 4which demarcate area 1. It is noted in this respect that gutters fromanother zone can likewise be transplanted to zone 2.

At the position of first edge 2 crop units of a crop are introduced intothe system for cultivating the crop, this being designated schematicallyin the figure with arrow 5, and at the position of second edge 3 fullygrown crop units are harvested and thereby removed from the system forcultivating a crop, this being designated schematically with arrow 6.The system for cultivating a crop comprises two zones, a first zone 7adjacent to the first edge 2 of predetermined area 1 and a second zone 8adjacent to the second edge 3 of predetermined area 1. First zone 7 andsecond zone 8 are further mutually adjacent at the position of asubstantially centrally located section 12 of predetermined area 1.Substantially centrally located section is defined here as the locationlocated at least a first distance removed from both first edge 2 andsecond edge 3, wherein the first distance is preferably at least 5% ofthe distance between first edge 2 and second edge 3, more preferably atleast 10%. Substantially centrally thus does not imply that it must lieat the mathematical midpoint between the first edge and the second edge.

A plurality of gutters, designated respectively with reference numerals9 and 10, are placed in both first zone 7 and second zone 8. Each gutterextends here substantially parallel to first edge 2 and second edge 3,and a guide 11 is provided for guiding gutters 9, 10 in the firstdirection. The first direction is substantially perpendicular to gutters9, 10. In the embodiment of FIG. 1 guide 11 lies on a plurality ofsupport profiles which are placed substantially horizontally (in thelongitudinal direction from edge 2 to 3). In the transverse direction(direction of the gutters) the support profiles lie at an inclinecorresponding to the drainage of the gutters. The number of supportprofiles (from edge 2 to 3) can be adjusted here on the basis of thesupport requirements of the gutters. The support profiles are preferablyinterrupted in their longitudinal direction at the position oftransition 12 from first zone 7 to second zone 8 such that gutters offirst zone 7 can also remain in this first zone and can be carried backto first edge 2, while the gutters of second zone 8 can remain in thissecond zone and are carried back to transition 12 after harvesting atthe position of second edge 3. The support profiles comprising guide 11preferably have a flat upper side such that gutters 9, 10 can slide onthe flat upper side of the support profiles. It is usually the case inpractice that zone 2 is divided in two in respect of the guide system.The support profiles and therefore also the guide system change at thepoint of division.

The technical difference between first zone 7 and second zone 8 lies inthe intermediate distance between adjacent crop units in the gutters.The intermediate distance 13 between crop units in gutters 9 of firstzone 7 is particularly considerably smaller than the intermediatedistance 14 between crop units in gutters 10 of second zone 8. Apartfrom this difference between intermediate distances 13 and 14, thetechnical construction and the operation of the system will besubstantially the same in first zone 7 as in the second zone. Zone 7 nowhas only one driven pull rod system (due to the limited length).

Characteristic of this system with two zones 7 and 8 is that atransition 12 can be designated where at least part of the crop unitsare transplanted or transferred from one gutter to another gutter. Inthe exemplary embodiment as shown in FIG. 1, all crop units aretransferred from gutter 9 at the position of transition 12 to one ormore gutters 10 of second zone 8 at the position of the transition. Thiscan take place automatically, mechanically or with intervention by aworker. In the embodiment of FIG. 1 gutters 9 remain in first zone 7 andare carried back to first edge 2. Gutters 10 of second zone 8 alsoremain in this zone, and when they reach the position of second edge 3they are carried back to transition 12 and there filled once again. Inan alternative embodiment the gutters continue from first zone 7 tosecond zone 8, and gutters are added at the position of transition 12 sothat part of the crop units can be transferred or transplanted from thegutters in the first zone to the additional gutters in order to thusincrease the intermediate distance between adjacent crop units in thegutters. For the sake of clarity the space between two crop units is inthis description referred to with the term intermediate distance, whilethe space between two gutters is referred to with the term distance.

In each zone 7, 8 gutters 9, 10 move in the first direction such that astart and an end can be defined for each zone 7, 8, wherein the end ofthe zone is the section where the gutters arrive when they move in thefirst direction. At the position of the start of each zone 7, 8 gutters9, 10 are positioned with a first distance between adjacent gutters 9,10, which first distance is designated respectively with referencenumerals 15 and 17. The first distance is minimal and, depending on theconfiguration of the system, can differ for first zone 7 and second zone8. Distance between gutters is defined as the distance between thecentral axes of the gutters. The first distance 17 of gutters 10 insecond zone 8 at the position of transition 12 is preferably greaterthan the width of the gutter +0 mm, preferably greater than the width ofthe gutter +5 mm (+1 mm), more preferably greater than the width of thegutter +10 mm, such that gutters 10 do not come into contact with eachother at the position of transition 12. When gutters 10 in second zone 8at the position of transition 12 are not pressed against each other,leaves of the crop are not pressed between adjacent gutters 10 either,such that the crop is not damaged. Advancing of gutters 10 duringfilling of the gutters or filling of at least part of the gutters alongtransition 12 is however considerably more difficult when gutters 10 maynot be pressed against each other. This is further explained hereinbelowwith reference to FIG. 7. At the position of the end of each zone 7, 8gutters 9, 10 display a second distance between adjacent gutters,designated respectively with reference numerals 16 and 18, which isconsiderably greater than first distance 15, 17. The second distance isa predefined maximum distance and, depending on the configuration of thesystem, can differ for first zone 7 and second zone 8.

The distance between adjacent gutters is increased from the firstdistance 15, 17 to the second distance 16, 18 in stepwise manner orcontinuously between start and end of the zone, over the length of eachzone 7, 8. The effect hereof is that the number of crop units per squaremetre decreases from the start of each zone toward the end of each zone.This has the result that the surface area per crop unit increases ineach zone from the start toward the end, which allows each crop unit togrow and also to be given the surface area necessary for this purpose.The surface area at the start of each zone is optimally utilized herebecause the distance between the gutters is small when the crop unitsare also small and require less surface area per crop unit, and eachcrop unit is given sufficient space to grow in each zone because thedistance between gutters increases from the start toward the end of eachzone.

At the position of transition 12 the end of first zone 7 is adjacent tothe start of second zone 8. The gutters of the first zone at theposition of transition 12 will hereby display a considerably greaterdistance between adjacent gutters than gutters 10 of second zone 8 atthe position of transition 12. Because of the combination of theconsiderable increase in the intermediate distance of crop units in onegutter in transition 12 from first zone 7 to second zone 8 and theconsiderable decrease in the distance between adjacent gutters alongtransition 12 from the first zone to second zone 8, the number of cropunits per m² can remain substantially constant along the transition fromfirst zone 7 to second zone 8. Substantially constant in this context ishere defined above. Tests have shown that this way of working with twozones 7 and 8 allows a crop to be cultivated in considerably moreefficient manner. The number of crop units per m² in predetermined area1 can hereby decrease continuously and/or in stepwise manner from firstedge 2 toward second edge 3. The crop units can be planted here at theposition of first edge 2 at a number of crop units per m² which isoptimized as a function of the size of the crop units which are planted.At the position of second edge 3 the crop units are harvested and eachcrop unit has reached full growth, and the number of crop units per m²is optimized as a function of the size of the fully grown crop units.This allows cultivation of a crop in a manner which optimizes surfacearea.

FIG. 2 shows a side view of a first zone 7 of the system of FIG. 1 andshows how gutters can be carried back to the start of the zone underguides 11, as indicated with arrow 19. The gutters are first emptied forthis purpose, wherein crop units are first transplanted from gutters 9of the first zone to gutters 10 of the second zone, which is indicatedwith arrow 20. Gutters 9 can then be carried via a transport systemunder guides 11 to the start of the first zone. At the position of thestart of the first zone gutters 9 are placed onto the start of the firstguide and filled with crop units. This is illustrated in the figure witharrow 21. The return of gutters 10 takes place under the guides.

FIG. 3 shows a perspective view of a gutter 10 of the second zone. Eachgutter 10 is preferably tubular or U-shaped in cross-section, with asubstantially slightly curved underside 25 on the inner side (thenutrient solution thus runs centrally through the gutter), and whereinthe gutter is preferably provided with downward protruding legs 23extending in the longitudinal direction of gutter 10. Protruding legs 23allow gutters 10 to be advanced in simple manner by means of a drivewhich is illustrated in FIG. 7. The tubular gutter requires no separatecover at the position where the U-shaped gutter is preferably providedon an upper side with a cover 24. A plurality of openings 22 are formedin the upper side or in these covers, wherein each opening is providedto receive one crop unit. Openings 22 can take on any dimensions andshape (round, oval, square, rectangular . . . ) and have an intermediatedistance 14, as discussed at length above. Gutters 9 of first zone 7 areconstructed in similar manner as the gutter shown in FIG. 3, howeverwith an intermediate distance between openings 22 which is considerablysmaller than the intermediate distance 14 shown in FIG. 3, whichdifference is illustrated in FIG. 6.

FIG. 4 shows a cross-section of a gutter 10 at the position of anopening 22 and shows a crop unit placed therein. The crop unit grows ina substrate (medium) 26. The roots of the crop grow in the medium butalso outside the medium, on the bottom of the gutter. The crop hasleaves and/or fruits 27. Leaves and/or fruits 27 typically extend abovecover 24 here, while the medium with roots 26 extends substantiallyunder cover 24. The advantage hereof is that the roots are shielded fromthe light. The water mixes with air and thereby takes up oxygen. Theoxygen is very important for the growth of roots and plant. This mannerof cultivating crops in gutters is generally known as NFT (Nutrient FilmTechnique), i.e. a thin film of nutrient solution flows through thegutter, in which the roots of the plant then develop, which is a form ofhydroponics.

FIG. 5 shows a predetermined area 1 in which a plurality of systemsaccording to the invention are placed and wherein a further area 28 isprovided which is adjacent to the first edge of predetermined area 1.This further area 28 is provided with a system which is similar to thesystem of each of the zones 7, 8, whereby a third zone is created, alsoreferred to as raising zone, which is provided just as the first zoneand the second zone with a guide and with a plurality of raisinggutters, wherein each raising gutter is provided to contain a pluralityof crop units with an intermediate distance smaller than firstintermediate distance 13 and wherein the further guide is provided tomove the raising gutters in the direction of the first edge ofpredetermined area 1, while the distance between adjacent raisinggutters increases. The same effect as described above in respect oftransition 12 will hereby occur in a further transition from raisingzone 28 to first zone 7. This means that the number of crop units per m²along the transition from the raising zone to the first zone can remainsubstantially constant. The surface area of further area 28 can also beoptimally utilized.

FIG. 6 shows three gutters of three different zones 7, 8 and 28. Thefigure shows here a gutter 10 of second zone 8, a gutter 9 of first zone7 and a gutter 29 of raising zone 28. The figure makes clear here thatthe intermediate distance between adjacent crop units in raising gutter29 is considerably smaller than the intermediate distance betweenadjacent crop units in gutter 9 of the first zone (extended raisingzone), and that this intermediate distance between the adjacent cropunits in first zone 7 is considerably smaller than the intermediatedistance between adjacent crop units in gutters 10 of second zone 8. Incombination with the reduction in the distance between adjacent gutters9, 10 and 29, this allows the number of crop units per m² to be keptsubstantially constant at each transition between zones.

FIG. 7 shows a preferred drive for application of the system accordingto the invention. It will be apparent here that different sorts andtypes of drive, including manual driving of the gutters wherein guttersare displaced manually, can be applied in order to execute the principleof the invention. A robotic system can also be used to advance thegutters. The preferred drive system of FIG. 7 comprises a drive rod, forinstance a pull rod, 30 with a plurality of catches 31. Drive rod 30 isprovided to move forward and backward as indicated in the figure witharrow 33. A plurality of such drive rods, each time controlling asegment of the length of the system, are provided over the length of thesystem for cultivating a crop which extends from first edge 2 to secondedge 3. A physical division of zone 2 and the resistance of materialsusually determine the length of a pull rod or guide system.

Each of the catches 31 can be tilted between a lying position in whichthe catch extends substantially parallel to drive rod 30 and an at leastpartially upward position in which catch 31 extends at least partiallyabove drive rod 30 so as to be able to hook behind a leg of a gutter andthus pull the gutter along in first direction 34. Catches 31 are herespring-loaded in upward direction such that they always tend to extendupward. When a downward force however engages on catches 31, catch 31will tilt counter to the spring force and extend substantially lying.Such a disposition allows gutters 10 to be driven when drive rod 30moves in first direction 34, while catches 31 extend upward and pull thegutters along. When the drive rod moves in the opposite direction,catches 31 will be pressed downward by gutters 10, counter to the springforce of catch 31, such that the gutters are not moved back. A one-waysystem for driving gutters is thus obtained hereby, wherein the distancebetween gutters can be changed in simple manner.

FIG. 7 shows on the right of the figure a further option wherein a partof drive rod 30 is covered at the top by a covering 35 which ensuresthat gutters 10 a which are situated above the covering cannot beco-displaced in first direction 34 by catches. This allows apredetermined segment to be advanced in a zone, while another segment isintentionally not advanced due to covering 35. This option becomesparticularly relevant when the harvesting at second edge 3 ofpredetermined area 1 and the planting and/or transplanting inrespectively first edge 2 and transition 12 do not take placesimultaneously.

Harvesting and not simultaneously transplanting (along transition 12)creates a gap in zone 8, which is filled once again during plantingand/or transplanting. Closing of this gap then typically takes place bymeans of a drive rod connected to a drive chain in combination with adrive rod which starts at transplanting zone 12 and ends N gutters pastcover plate 35. The drive rod connected to a chain is typically situatedin a starting position under the gutters at the position of covering 35.During harvesting the gutters will be co-displaced by the drive rodsending at the second edge and starting at covering 35. A gap, which hasto be filled during transplanting, will result behind cover plate 35. Inorder to fill the gap the pull rod on the chain will first move forwardN positions so that the catches are pulled past cover plate 35 andextend upward. The drive rod which starts at transplanting zone 12 willthen push N gutters past the cover plate. This process is repeated untilthe chain has moved the gutters over the whole gap. A gap in a fieldwith gutters can thus be filled without gutters having to be pushedagainst each other.

The drive as shown in FIG. 7 provides many options for designing andcontrolling the gutters in their movement in the first direction. Thisdrive of FIG. 7 particularly allows gutters to be added at the start ofa zone, without these gutters having to be pushed against each other.The drive allows these gutters to be pulled along with a distancebetween adjacent gutters, wherein no leaves can be pressed betweenadjacent gutters, as already stated above.

FIG. 8 shows a graph which displays the effect of the use of a system asshown in FIG. 1. The graph shows the number of days a crop has beengrowing on the horizontal axis, while the number of crop units per m² isshown on the vertical axis. The values included in the graph are only anexample, and it will be apparent that these values can differconsiderably depending on the type of crop. The principles shown by thisgraph are however characteristic of the system according to theinvention and are therefore generally applicable. The figure shows threestages, wherein first stage 37 indicates the raising stage. In theexample of FIG. 8 crop units are planted in the raising gutter at a rateof 216 crop units per m².

After raising stage 37 the crop units are transplanted from gutters 29to gutters 9 (extended raising stage zone 7) at the position of firstedge 2, where gutters 9 are then situated close together such that 108crop units per m² are situated in gutters 9 at the position of firstedge 2. By increasing the distance between adjacent gutters in firstzone 7, in the example of FIG. 8 in steps, the number of crop units perm² systematically decreases to 49 crop units per m² when gutters 9 areat the position of transition 12. The crop units are then transferred ortransplanted to gutters 10 in second zone 8 at, in the example of FIG.8, a rate of 38 crop units per m². This number of crop units of 38 perm² is obtained while the gutters in second zone 8 are situated closetogether, this by considerably increasing the intermediate distancebetween adjacent crop units in gutter 10 relative to first zone 7. Byincreasing the distance between the gutters in second zone 8 while thegutters are moving from transition 12 to second edge 3, the number ofcrop units per m² decreases systematically in order to give the cropspace to reach full growth. At the position of second edge 3 the cropunits have a density of about 15 crop units per m², crop units havereached full growth, and can be harvested. The surface area ofpredetermined area 1 is in this way optimally utilized.

It will be apparent on the basis of the above description that, when theclaim defines that the guide (pull rod) is provided for guiding thegutters in a first direction extending from a first edge to a secondedge of the area, this does not mean that one guide covers the wholeroute from the first edge to the second edge. The guides will indeed allmove in the first direction. This first direction extends from the firstto the second edge. The plurality of guides together will ensure thatthe crop units move from the first edge to the second edge.

The skilled person will be able to understand the operation andadvantages of the invention, as well as the different embodimentsthereof, on the basis of the figures and the description. It will beapparent here that the description and the figures are intended solelyfor the purpose of understanding the invention and not to limit theinvention to a few embodiments or examples used therein. It is thereforestressed that the scope of protection will be defined solely in theclaims.

The invention claimed is:
 1. A system for cultivating a crop,comprising: a guide for guiding a plurality of gutters in apredetermined area, wherein each gutter is provided to contain aplurality of crop units of the crop and wherein the guide is provided toguide the gutters in a first direction extending from a first edge to asecond edge of the area, wherein the guide is further provided togradually increase the distance between adjacent gutters in said firstdirection, such that the number of crop units per square metre in thearea substantially decreases from the first edge to the second edge,wherein the area comprises a first zone adjacent to the first edge and asecond zone adjacent to the second edge, and wherein each gutter in thefirst zone is provided to contain crop units with a first intermediatedistance and wherein each gutter in the second zone is provided tocontain crop units with a second intermediate distance, and wherein thefirst intermediate distance is considerably smaller than the secondintermediate distance and wherein the distance between adjacent guttersin the first zone at the position of a transition from the first zone tothe second zone is considerably greater than the distance betweenadjacent gutters in the second zone at the position of the transition.2. The system for cultivating a crop as claimed in claim 1, wherein theratio of the first intermediate distance and the second intermediatedistance and the ratio of the distance between adjacent gutters in thesecond zone and in the first zone at the position of the transition ischosen such that the number of crop units per square metre remainssubstantially constant along the transition.
 3. The system forcultivating a crop as claimed in claim 1, wherein the guide comprises adrive for moving the gutters in the first direction, and wherein thedrive is provided to change the distance between adjacent gutters insaid first direction.
 4. The system for cultivating a crop as claimed inclaim 3, wherein the drive is formed by a plurality of pull rods andwherein at least one covering of a pull rod system connected to a chainand a separate pull rod system are provided in order to fill the gapcreated in the field with crop units, such that the gutters are pulledinto this gap.
 5. The system for cultivating a crop as claimed in claim1, further comprising a device for transplanting at least part of thecrop units along said transition from the first zone to the second zone.6. The system for cultivating a crop as claimed in claim 5, wherein thedevice is provided to transplant all crop units from gutters in thefirst zone to gutters in the second zone.
 7. The system for cultivatinga crop as claimed in claim 1, wherein each gutter comprises a pluralityof means for containing a crop unit, this plurality of means havingpredetermined intermediate distances in the longitudinal direction ofthe gutter.
 8. The system for cultivating a crop as claimed in claim 7,wherein the gutters are tubular or U-shaped in cross-section with a lid,wherein the plurality of means are formed as openings in the cover, andwherein each opening is formed to contain a crop unit such that mediumand roots of the crop unit are situated substantially under the coverwhile leaves of the crop unit are situated substantially above thecover.
 9. The system for cultivating a crop as claimed in claim 1,wherein the gutters are placed in a draining manner and wherein thesystem comprises at the position of one end of the gutters a waterdosing system and at the position of another end of the gutters a watercollecting system, such that water flows through the gutters in acontrolled manner during use of the system.
 10. The system forcultivating a crop as claimed in claim 9, wherein the water collectingsystem is operatively connected to the water dosing system such thatwater can be recuperated.
 11. The system for cultivating a crop asclaimed in claim 9, wherein a plurality of water dosing systems and aplurality of water collecting systems are provided so that a differentquantity of water and/or water with different properties can be suppliedto various of said gutters.
 12. The system for cultivating a crop asclaimed in claim 1, wherein the system further comprises a raising zonewith a further guide for guiding a plurality of raising gutters in afurther area adjacent to the first edge, wherein each raising gutter isprovided to contain a plurality of the crop units with a furtherintermediate distance which is considerably smaller than the firstintermediate distance, wherein the guide is provided to graduallyincrease the distance between adjacent raising gutters in said firstdirection and wherein the distance between adjacent raising gutters atthe position of a further transition from the raising zone to the firstzone is considerably greater than the distance between adjacent guttersat the position of the further transition, such that the number of cropunits per square metre remains substantially constant along the furthertransition.
 13. A method for cultivating a crop, comprising: plantingcrop units of the crop in a plurality of gutters at a position of afirst edge of a predetermined area; guiding the plurality of gutters ina first direction which extends from the first edge to a second edge ofthe predetermined area, wherein the distance between adjacent guttersgradually increases during the guiding such that the number of cropunits per square metre decreases from the first edge to the second edge;harvesting the crop units at the position of the second edge; whereinthe method further comprises: transplanting at least part of the cropunits along a transition from a first zone of the area adjacent to thefirst edge to a second zone of the area adjacent to the second edge,such that each gutter in the first zone is provided to contain cropunits with a first intermediate distance and each gutter in the secondzone is provided to contain crop units with a second intermediatedistance, wherein the first intermediate distance is considerablysmaller than the second intermediate distance and wherein the distancebetween adjacent gutters in the first zone at the position of thetransition is considerably greater than the distance between adjacentgutters in the second zone at the position of the transition.
 14. Themethod for cultivating a crop as claimed in claim 13, furthercomprising: advancing at least part of the plurality of gutters in thefirst direction by means of a drive.